German Patent No. DE 195 20 300 describes a device for detecting a leak in a fuel supply system in an internal combustion engine, in particular in a compression-ignition internal combustion engine. In the device described therein, the fuel is conveyed by at least one fuel pump under pressure from a fuel reservoir into a so-called high-pressure zone. From the high-pressure zone the fuel reaches the individual combustion chambers of the internal combustion engine via injectors. The pressure in the high-pressure zone is usually detected by a pressure sensor. This pressure sensor is normally used for setting or regulating the pressure in the high-pressure zone. In the related art the pressure is analyzed by detecting the pressure variation and comparing it with an expected pressure variation. In the event of a difference between an expected pressure variation and the actual pressure variation, the device detects a leak.
The disadvantage in this type of error monitoring is that what is detected is only whether or not a leak has occurred.